1. Field of the Invention
The present invention is related generally to embryonic-like stem cells isolated from human umbilical cord blood.
2. Background of the Invention
The increasing prevalence of chronic human diseases, e.g. cardiovascular disease, diabetes, and neuronal degenerative diseases, presents a challenge to find more effective therapies. Stem cell-based therapy, including embryonic and adult stem cells, provides a rational treatment tool for regenerative medicine and has potential to revolutionize modern therapeutics [A. Vats, R. C. Bielby, N. S. Tolley, R. Nerem, J. M. Polak, Stem cells, Lancet 366 (2005) 592-602; M. A. Hussain, N. D. Theise, Stem-cell therapy for diabetes mellitus, Lancet 364 (2004) 203-205; C. M. Rice, N. J. Scolding, Adult stem cells—reprogramming neurological repair? Lancet 364 (2004) 193-199; L. M. Hoffman, M. K. Carpenter, Characterization and culture of human embryonic stem cells, Nat Biotechnol. 23 (2005) 699-708]. Because of their high potential for self renewal and pluripotent differentiation capability, embryonic stem (ES) cells have become a very active area of investigation [A. Vats, R. C. Bielby, N. S. Tolley, R. Nerem, J. M. Polak, Stem cells, Lancet 366 (2005) 592-602; L. M. Hoffman, M. K. Carpenter, Characterization and culture of human embryonic stem cells, Nat Biotechnol. 23 (2005) 699-708; K. H. Wilan, C. T. Scott, S. Herrera, Chasing a cellular fountain of youth, Nat Biotechnol. 23 (2005) 807-815]. Ethical concerns, however, have limited their availability and practical usefulness [C. Dennis, Check E, ‘Ethical’ routes to stem cells highlight political divide, Nature 437 (2005) 1076-1077; M. Evans, Ethical sourcing of human embryonic stem cells—rational solutions? Nat Rev Mol Cell Biol. 6 (2005) 663-667]. Leaving aside these ethical concerns, using in vitro fertilization (IVF) and altered nuclear transfer (ANT) to generate ES cells is made problematic by the complexity of required technologies [M. Evans, Ethical sourcing of human embryonic stem cells—rational solutions? Nat Rev Mol Cell Biol. 6 (2005) 663-667; D. A. Melton, G. Q. Daley, C. G. Jennings, Altered nuclear transfer in stem-cell research—a flawed proposal, N Engl J Med. 351 (2004) 2791-2792].
Recently, human umbilical cord blood has been used as a source of stem cells to repopulate the hematopoietic system and other organs [J. Bonde, D. A. Hess, J. A. Nolta, Recent advances in hematopoietic stem cell biology, Curr Opin Hematol. 11 (2004) 392-398; K. K. Ballen, New trends in umbilical cord blood transplantation, Blood 105 (2005) 3786-3792; D. A. Peterson, Umbilical cord blood cells and brain stroke injury: bringing in fresh blood to address an old problem, J Clin Invest. 114 (2004) 312-314; V. Silani, L. Cova, M. Corbo, A. Ciammola, E. Polli, Stem-cell therapy for amyotrophic lateral sclerosis, Lancet 364 (2004) 200-202]. Cord blood provides an abundant source for generation of stem cells, including mesenchymal stem cells [K. Bieback, S. Kern, H. Kluter, H. Eichler, Critical parameters for the isolation of mesenchymal stem cells from umbilical cord blood, Stem Cells 22 (2004) 625-634; E. J. Gang, S. H. Hong, J. A. Jeong, S. H. Hwang, S. W. Kim, I. H. Yang, C. Ahn, H. Han, H. Kim, In vitro mesengenic potential of human umbilical cord blood-derived mesenchymal stem cells, Biochem Biophys Res Commun. 321 (2004) 102-108; G. Kogler, S. Sensken, J. A. Airey, T. Trapp, M. Muschen, N. Feldhahn, S. Liedtke, R. V. Sorg, J. Fischer, C. Rosenbaum, S. Greschat, A. Knipper, J. Bender, O. Degistirici, J. Gao, A. I. Caplan, E. J. Colletti, G. Almeida-Porada, H. W. Muller, E. Zanjani, P. Wernet, A new human somatic stem cell from placental cord blood with intrinsic pluripotent differentiation potential, J Exp Med. 200 (2004) 123-135] and monocyte-derived stem cells [Y. Zhao, T. Mazzone, Human umbilical cord blood-derived f-macrophages retain pluripotentiality after thrombopoietin expansion, Exp Cell Res. 310 (2005) 311-318]. Stem cells expressing ES molecular markers have been reported from cord blood after removal of hematopoietic cells (including deletion of all leukocyte common antigen CD45 positive cells) [C. P. McGuckin, N. Forraz, M. O. Baradez, S, Navran, J. Zhao, R. Urban, R. Tilton, L. Denner, Production of stem cells with embryonic characteristics from human umbilical cord blood, Cell Prolif. 38 (2005) 245-55]. However, the scarcity of this previously-described cell population [C. P. McGuckin, N. Forraz, M. O. Baradez, S, Navran, J. Zhao, R. Urban, R. Tilton, L. Denner, Production of stem cells with embryonic characteristics from human umbilical cord blood, Cell Prolif. 38 (2005) 245-55] in cord blood significantly restricts its practical application.
Several other embryonic-like stem cells derived from adult sources rather than embryonic sources have also been disclosed. For example, U.S. Pat. No. 7,045,148, United States Patent Applications Serial Numbers 2005/0148034, 2005/0118715, 2004/0028660, 2003/0235909, 2002/0160510, 2003/0180269 and International Patent Application Number WO 03/068937 disclose embryonic-like stem cells extracted from the placenta or from the umbilical cord blood. United States Patent Application Serial Number 2006/0078993 discloses embryonic-like stem cells derived from the amniotic membrane of umbilical cord. The stem cells disclosed in these patents or patent applications are of mesenchymal origin, which do not express the CD45 marker (CD45−). In another example, United States Patent Application Serial Number 2006/0147426 discloses stem cells derived from human bone marrow.
Accordingly, better methods of isolating autologous stem cells are needed to overcome the challenges faced by current stem cell research, such as ethical concerns and immune rejection. Accordingly, there is a need in the art for methods of isolation of stem cells with embryonic-stem cell characteristics from readily available sources.